While in elemental form, you gain +100% fortification. If you are a Warforged, you are no longer considered a Living Construct, and so are immune to Repair spells, but can be healed normally by Positive Energy spells. When Elemental Apotheosis is active, casting a spell of that tree's element on a creature that is immune to that element, that creature becomes vulnerable to that element for a short time. While in Water Elemental form, you also gain an additional +20 Cold Spell Power, +2% Cold Spell Critical Chance, and a +1 bonus to caster level and max caster level for Cold and Water spells, but your air, earth and fire spells have a -3 penalty to caster level and max caster level. You also gain a +10 racial bonus to Cold resistance, +20 Physical Resistance Rating, +20 Swim, and a -10 penalty to Fire resistance. While in Elemental Form, your spells also cost an additional 10% Spell Points to cast.

You also gain the following passive benefits, even while not in elemental form:

Awaken Elemental Weakness: Cold: You are able to curse an enemy, increasing Cold damage they take by 15%. When cast on a creature that is immune to that tree's Element, it makes them vulnerable to that element for a short period of time. (Activation Cost: 5 Spell Points. Cooldown: 20 seconds.)